Photon imaging detectors using semiconductors are known in the art. Typically, the semiconductor is in the form of a sheet, and electrodes are formed on either side of the sheet. X-ray or γ-ray photons that interact with the semiconductor generate electron-hole pairs, and the pairs are detected as charges at the electrodes. One semiconductor which has been successfully used as an imaging detector is cadmium zinc telluride (CZT).
A document, “Signals induced in semiconductor gamma-ray imaging detectors” by J. D. Eskin et al., published in the Journal of Applied Physics, Vol. 85, pp. 647ff. (1999), is incorporated herein by reference. The document describes the signals generated in a semiconductor sheet, typically CZT, when the electrodes formed on the semiconductor are in the form of pixels.
U.S. Pat. No. 7,078,669 to Mikkelsen et al., whose disclosure is incorporated herein by reference, describes a readout circuit for reading active pixels in a sensor. The sensor uses a fast shaper and a slow shaper connected to each pixel. The fast shaper is used to establish an incident time of radiation striking the pixel. The slow shaper is used for determining the peak energy value of the pixel if it goes active.
However, notwithstanding existing systems, an improved method for reading imaging detectors would be advantageous.